/* Microsoft Reference Implementation for TPM 2.0
 *
 *  The copyright in this software is being made available under the BSD License,
 *  included below. This software may be subject to other third party and
 *  contributor rights, including patent rights, and no such rights are granted
 *  under this license.
 *
 *  Copyright (c) Microsoft Corporation
 *
 *  All rights reserved.
 *
 *  BSD License
 *
 *  Redistribution and use in source and binary forms, with or without modification,
 *  are permitted provided that the following conditions are met:
 *
 *  Redistributions of source code must retain the above copyright notice, this list
 *  of conditions and the following disclaimer.
 *
 *  Redistributions in binary form must reproduce the above copyright notice, this
 *  list of conditions and the following disclaimer in the documentation and/or
 *  other materials provided with the distribution.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ""AS IS""
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 *  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 *  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "Tpm.h"
#include "Hash_fp.h"

#if CC_Hash  // Conditional expansion of this file

/*(See part 3 specification)
// Hash a data buffer
/*
Part 3, 15.4 TPM2_Hash
This command performs a hash operation on a data buffer and returns the results.
NOTE If the data buffer to be hashed is larger than will fit into the TPM’s input buffer, then the sequence
hash commands will need to be used.
此命令对数据缓冲区执行哈希操作并返回结果。
注意 如果要散列的数据缓冲区大于 TPM 的输入缓冲区，则需要使用序列散列命令。

If the results of the hash will be used in a signing operation that uses a restricted signing key, 
then the ticket returned by this command can indicate that the hash is safe to sign.
如果散列的结果将用于使用受限签名密钥的签名操作，则此命令返回的票证可以表明散列可以安全签名。

If the digest is not safe to sign, then the TPM will return a TPMT_TK_HASHCHECK with the hierarchy set to 
TPM_RH_NULL and digest set to the Empty Buffer.
If hierarchy is TPM_RH_NULL, then digest in the ticket will be the Empty Buffer.
如果摘要用于签名不安全，则 TPM 将返回一个 TPMT_TK_HASHCHECK，层次结构设置为 TPM_RH_NULL，摘要设置为空缓冲区。
如果层次结构是 TPM_RH_NULL，则票证中的摘要将是空缓冲区。

*/

TPM_RC
TPM2_Hash(
    Hash_In         *in,            // IN: input parameter list
    Hash_Out        *out            // OUT: output parameter list
    )
{
    HASH_STATE          hashState;

// Command Output

    // Output hash
        // Start hash stack
    out->outHash.t.size = CryptHashStart(&hashState, in->hashAlg);
        // Adding hash data
    CryptDigestUpdate2B(&hashState, &in->data.b);
        // Complete hash
    CryptHashEnd2B(&hashState, &out->outHash.b);

    // Output ticket
    out->validation.tag = TPM_ST_HASHCHECK;
    out->validation.hierarchy = in->hierarchy;

    if(in->hierarchy == TPM_RH_NULL)
    {
        // Ticket is not required
        out->validation.hierarchy = TPM_RH_NULL;
        out->validation.digest.t.size = 0;
    }
    /*
    If the data used to create the digest does not have TPM_GENERATED_VALUE as its first octets, 
    then the response to TPM2_Hash() or TPM2_SequenceComplete() will contain a ticket indicating 
    that the digest may be signed with a restricted signing key.
    
    如果用于创建摘要的数据没有将 TPM_GENERATED_VALUE 作为其第一个八位字节，则对 TPM2_Hash() 或 TPM2_SequenceComplete() 
    的响应将包含一个票证，表明摘要可以使用受限签名密钥进行签名。
    */
    else if(in->data.t.size >= sizeof(TPM_GENERATED_VALUE)
            && !TicketIsSafe(&in->data.b))
    {
        // Ticket is not safe
        out->validation.hierarchy = TPM_RH_NULL;
        out->validation.digest.t.size = 0;
    }
    else
    {
        // Compute ticket
        TicketComputeHashCheck(in->hierarchy, in->hashAlg,
                               &out->outHash, &out->validation);
    }

    return TPM_RC_SUCCESS;
}

#endif // CC_Hash